Preparation and photoluminescence properties of the Eu2+, Sm3+ co-doped Li2SrSiO4 phosphors

A series of Eu2+ and Sm3+ co-doped Li2SrSiO4 phosphors are prepared by the high temperature solid-state reaction. The morphology, structure and spectroscopic properties of the prepared samples are characterized by scanning electron microscopy, X-ray diffraction, diffuse reflection spectra, photoluminescence spectra and electron paramagnetic resonance spectra, respectively. The effect of Sm3+ doping concentration on the photoluminescence intensity of the prepared samples is also investigated. The results indicate that the crystal structure of Li2SrSiO4 is not changed with the Eu2+, Sm3+ co-doping. The spherical-like particle size of the obtained product is about 20–30 nm in diameter. When the Sm3+ concentration is 0.3 mol% and the Eu2+ concentration is 0.7 mol%, the phosphors show the maximum emission intensity, which is 50% higher than that of Eu2+ doped Li2SrSiO4. Excited at 420 nm, the phosphor presents a single broad emission band peaking at 558 nm, which is ascribed to the 4f65d1 → 4f7 transitions of Eu2+ and 4G5/2 → 6H5/2 and 4G5/2 → 6H7/2 transitions of Sm3+. The Commission International de I′Eclairage chromaticity coordinates of Li2SrSiO4:0.7 mol% Eu2+, 0.3 mol% Sm3+ are x = 0.28, y = 0.28.

► Eu2+/Sm3+ co-doped Li2SrSiO4 phosphors were successfully synthesized for the first time.
► The co-doping of Eu2+/Sm3+ can significantly improve the emission intensity of this phosphor.
► White light can be obtained by integrating this phosphor with blue LED chip.